Unionist parties who supported a stone monument at Stormont to mark the centenary of partition must pay for its installation, the SDLP has said.
The Assembly Commission, the MLA-led board that oversees Stormont's administration, has agreed to site the stone to the east of Parliament Buildings, close to the recently-restored tomb of former Northern Ireland prime minister James Craig and his wife Cecil.
The three main unionist parties have previously committed to pay for the 2.5m high monument, which depicts Northern Ireland.
It is understood the Portland stone sculpture cost up to £8,000 to carve. However, the cost of installation is estimated at £18,000.
It has been suggested the additional cost will be borne by the DUP, UUP and TUV, based proportionally on the number of MLAs each party has.
None of the parties has commented on the issue and they are understood to be waiting for official confirmation of the installation costs from the Assembly Commission.
An SDLP spokesperson said the stone's installation costs should be met by the unionist parties who had "guaranteed" to cover all expenses.
"That’s the fundamental basis on which we did not block the proposal," the spokesperson said.
"The reported cost of £18,000 to co-locate it at Craigavon’s tomb must be met in full by its proponents."
The party also called for the Stormont estate and parliament buildings to become "more representative of the history and ambitions of our entire society".
"The SDLP made clear that a review of how other traditions are represented is now necessary – and not just for nationalism but including the trade union movement, women’s rights, the LGBT+ community and the rich diversity of our whole society," the spokesperson said.
"This is about mutual respect."